Highly Sensitive and Selective Electrochemical Determination of Sunset Yellow in Food Products Based on AuNPs/PANI-co-PoAN-co-PoT/GO/Au Electrode

Abstract

A terpolymer poly(aniline-co-o-anisidine-co-o-toluidine)/graphene oxide nanocomposite with a common abbreviation [PANI-co-PoAN-co-PoT/GO1-5] was synthesized by the well-known in situ oxidative polymerization process with ultrasonic assistance. The morphological characteristics were investigated by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Moreover, the complete performance was studied by Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), and electrical conductivity measurements. All nanocomposites displayed a maximum composite degradation temperature (CDTmax) in the range of 295.6-322.8 °C, which is higher than that shown for the pure terpolymer (295.4 °C). The conductivities of the pure PANI-co-PoAN-co-PoT and PANI-co-PoAN-co-PoT/GO1-5 nanocomposites display conductive behavior. An electrochemical sensor comprising the [PANI-co-PoAN-co-PoT/GO] nanocomposite and Au nanoparticles was successfully coated onto a gold electrode [AuNPs/PANI-co-PoAN-co-PoT/GO/Au] through an electrochemical process and was utilized to detect sunset yellow (SY). The electrochemical behavior of the modified electrochemical sensor towards the oxidation of SY was examined by cyclic voltammetry (CV) and square wave voltammetry (SWV). SWV resulted in a linear calibration curve for SY on AuNPs/PANI-co-PoAN-co-PoT/GO/Au over the range of (5 μM-500 μM), and the limit of detection was estimated to be 0.0142 μM. These results suggest that the obtained AuNPs/PANI-co-PoAN-co-PoT/GO/Au was able to detect SY with excellent stability, good selectivity, low detection limit and high sensitivity.